Sink



FIG. 1 is a perspective view of a sink showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof; and,

FIG. 6 is a rear elevational view thereof.

The broken line showing of faucet holes and a drain hole is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a sink, as shown and described. 